Maturation‐dependent control of vocal temporal plasticity in a songbird

Abstract

Birdsong is a unique model to address learning mechanisms of the timing control of sequential behaviors, with characteristic temporal structures consisting of serial sequences of brief vocal elements (syllables) and silent intervals (gaps). Understanding the neural mechanisms for plasticity of such sequential behavior should be aided by characterization of its developmental changes. Here, we assessed the level of acute vocal plasticity between young and adult Bengalese finches, and also quantified developmental change in variability of temporal structure. Acute plasticity was tested by delivering aversive noise bursts contingent on duration of a target gap, such that birds could avoid the noise by modifying their song. We found that temporal variability of song features decreased with birds' maturation. Noise-avoidance experiments demonstrated that maximal changes of gap durations were larger in young that in adult birds. After these young birds matured, the maximal change decreased to a similar level as adults. The variability of these target gaps also decreased as the birds matured. Such parallel changes suggest that the level of acute temporal plasticity could be predicted from ongoing temporal variability. Further, we found that young birds gradually began to stop their song at the target gap and restart from the introductory part of song, whereas adults did not. According to a synaptic chain model for timing sequence generation in premotor nuclei, adult learning would be interpreted as adaptive changes in conduction delays between chain-to-chain connections, whereas the learning of young birds could mainly depend on changes of the connections. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 995-1006, 2017.

Intrinsic motivation for singing in songbirds is enhanced by temporary singing suppression and regulated by dopamine

“…Additionally, similar mechanisms could account for the observed age-dependent declines of overall singing rate and of singing motivation enhancement caused by singing suppression. Although young adult zebra finches maintain and optimize song structure through vocal practice, song plasticity gradually declines with age 10 , 11 , 42 . Given the reduced plasticity of song structure in older adult birds, it is possible that less vocal practice is sufficient to maintain song structure even after relatively long singing suppression.…”

Zebra finches show spatial avoidance of near but not far distance traffic noise

“…To test whether noise becomes so aversive that it affects spatial preferences requires testing paradigms that allow individuals to choose among identical locations only differing in noise characteristics as well as suitable model species. Domesticated zebra finches and other related estrildid finches have already been successfully studied in experiments investigating the effect of masking noise on their vocal communication (Cynx et al, 1998;Tumer & Brainard, 2007;Potvin & MacDougall-Shackleton, 2015;Villain et al, 2016;Tachibana et al, 2017). These studies, however, passively exposed birds to noise without offering quiet(er) alternative spaces.…”

Auditory and sexual preferences for a father’s song can co-emerge in female Bengalese finches

“…Regarding song learning in males, one study reported that Bengalese finch juveniles can imitate the song of a tutor they interacted with from 35 to 70 dph [ 45 ]. When juveniles have normal auditory and social access to a tutor(s), the basic acoustical structure of song elements imitated from the tutor(s) is already visible and stable at 80–90 dph [ 29 , 46 ]. Therefore, if females are separated from their family earlier in development and are allowed only a limited period or amount of interaction with their father, the strength of the preference for the father’s song may become weaker than what we observed in this study.…”